Vinyl acetate-ethylene copolymer emulsion and paper coating composition based on the same

ABSTRACT

The present invention relates to a vinyl acetate-ethylene copolymer emulsion and a paper coating composition based on the same. More specifically, the present invention relates to a vinyl acetate-ethylene copolymer emulsion based paper coating composition with low odor. The present invention also relates to processes for preparing the vinyl acetate-ethylene copolymer emulsion and the paper coating composition, and uses thereof.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vinyl acetate-ethylene copolymeremulsion and a paper coating composition based on the same. Morespecifically, the present invention relates to a vinyl acetate-ethylenecopolymer emulsion based paper coating composition with low odor. Thepresent invention also relates to processes for preparing the vinylacetate-ethylene copolymer emulsion and the paper coating composition,and uses thereof.

2. Description of the Related Art

Aqueous emulsions, such as styrene-butadiene copolymer emulsion,styrene-acrylate copolymer emulsion, acrylate copolymer emulsion, vinylacetate homopolymer emulsion, vinyl acetate-ethylene copolymer emulsion,etc., are commonly used as binder for paper surface coating in paperindustry, and styrene-butadiene copolymer emulsion are the most widelyused aqueous emulsion among others. With the advancement in modernprinting package techniques, the requirements to the papers for using inprinting and packing are also enhancing, in particular to those printingpackages with high qualities such as cigarette package and food packagewhich require that the package material per se has a low odor.Especially as the application of Ultra-Violet (UV) curable ink andelectron beam radiation curable ink printing techniques recently, ahigher requirement to the odor of the package material and therefore tothe odor of the emulsion for surface coating has raised. However,traditional aqueous emulsions tend to be odorous and cannot meet therequirement of low odor paper coating, especially printing packages withhigh qualities such as cigarette package and food package.

Although a low odor aqueous emulsion is required in the art, fewresearches have been done to lower the odor of the aqueous emulsion usedin paper making industry, and the factors which directly influence theodor of the emulsion are still unknown up to now. Furthermore, the odorsof various kinds of emulsion polymers which have already cured under UVand electron beam radiation are still unpredictable respectively to thetechnicians in the art based on their past experiences.

Therefore, a need still exists for low odor aqueous emulsion and papercoating composition based on the same for application in printingpackages with high qualities.

BRIEF SUMMARY OF THE INVENTION

It has been surprisingly found by the present inventors that, by using aspecific vinyl acetate-ethylene copolymer emulsion according to thepresent invention instead of commonly used aqueous emulsion such asstyrene-butadiene emulsion as binder for paper coating compositions,especially high qualities paper coating compositions used in UV curableink and electron beam radiation curable ink, such as those used incigarette package and food package, a vinyl acetate-ethylene copolymeremulsion and a paper coating composition based on the same withextraordinary low odor are obtained.

The vinyl acetate-ethylene copolymer emulsion according to the presentinvention is obtained through aqueous emulsion polymerization of vinylacetate and ethylene. It has been surprisingly found by the presentinventors that the package paper made by using the inventive vinylacetate-ethylene copolymer emulsion as binder for paper surface coatingexhibits a extremely low odor after application of Ultra-Violet (UV)curable ink and electron beam radiation curable ink printing techniques,which can meet the low odor requirement sufficiently as needed by themarket. Without wishing to be bound by any theory, but the applicantbelieves that the low odor performances as provided by the vinylacetate-ethylene copolymer emulsion according to the present inventionis partially attributed to following factors, such as thestructure/composition properties of the vinyl acetate-ethylene copolymeremulsion and/or its advantages over commonly used styrene-butadienecopolymer emulsion, which could include: the vinyl acetate-ethylenecopolymer emulsion is free of organic phenylic monomer, and thepolymerization process is carried out without addition of phenylicderived monomer, therefore the residue of volatile phenylic derivativewhich has special odor such as 4-phenyl cyclohexene is avoided;ethylene, one of the monomers, is gas, thus can hardly retained in theemulsion; the vinyl acetate monomer and other possible volatile organicresidues can be further reduced by chemical and physical process duringor after the end of the polymerization, whereby the content of residuevinyl acetate monomer can be reduced to less than about 800 ppm,preferably less than about 600 ppm, more preferably less than about 400ppm; furthermore, vinyl acetate ethylene copolymer will not releaseodorous substances by further chemical reaction under exposure to UV orelectron beam radiation.

Thus, one object of the present invention is to provide a low odor vinylacetate-ethylene copolymer emulsion.

Another object of the present invention is to provide a process forpreparing said vinyl acetate-ethylene copolymer emulsion.

Still another object of the present invention is to provide a use of thevinyl acetate-ethylene copolymer emulsion for low odor paper coatingcomposition.

Furthermore, one object of the present invention is to provide a lowodor paper coating composition.

Another object of the present invention is to provide a process forpreparing said low odor paper coating composition.

Still another object of the present invention is to provide a use of thelow odor paper coating composition in printing packages with highqualities, such as cigarette package and food package.

DETAILED DESCRIPTION OF THE INVENTION

For the purposes of this description, unless otherwise indicated, allnumbers expressing quantities of ingredients, reaction conditions, andso forth used in the description and claims are to be understood asbeing modified in all instances by the term “about”. Accordingly, unlessindicated to the contrary, the numerical parameters set forth in thefollowing description and attached claims are approximations that mayvary depending upon the desired properties sought to be obtained by thepresent invention. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should at least be construed in light of thenumber of reported significant digits and by applying ordinary roundingtechniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific Examples are reported as precisely aspossible. Any numerical value, however, inherently contain certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements.

It is noted that, as used in this description and the appended claims,the singular forms “a”, “an” and “the” include plural referents unlessexpressly and unequivocally limited to one referent.

According to one aspect of the present invention, a vinylacetate-ethylene copolymer-based emulsion for low odor paper coatingcomposition is provided, wherein the copolymer comprises, based on thetotal weight of the copolymer:

-   (1) about 65-95 pphm (parts by weight/100 parts by weight of    monomers used for preparing the emulsion), preferably about 75-90    pphm of a moiety derived from vinyl acetate;-   (2) about 5-35 pphm, preferably about 10-20 pphm of a moiety derived    from ethylene; and-   (3) about 0-10 pphm, preferably about 0-5 pphm of a moiety derived    from other comonomers or functional monomers,    wherein the copolymer-based emulsion is formed by emulsion    polymerization of the monomers in the presence of about 1-5 pphm,    preferably about 2-5 pphm, more preferably about 2-4 pphm of a    surfactant and about 0-10 pphm, preferably about 0-5 pphm of a    polymeric protective colloid as emulsifier/protective colloid.

In some non-limiting embodiments of the present invention, the monomersused in emulsion polymerization can be composed of about 65-95 pphm ofvinyl acetate, about 5-35 pphm of ethylene and about 0-10 pphm of othercomonomers or functional monomers. Examples of other comonomers orfunctional monomers suitable for the present invention include, but notlimited to, one or more selected from the group of:

-   -   vinyl esters of polyacid, wherein the specific monomer can        include:

wherein each of R₁ and R₂ is hydrogen or alkyl group, provided that thetotal carbon atom number of R₁ and R₂ is from 1 to 14;

-   -   acrylates, wherein the specific monomer can include:

wherein R₃ is hydrogen or alkyl group with 1 to 16 carbon atom(s);

-   -   methacrylates, wherein the specific monomer can include:

wherein R₄ is hydrogen or alkyl group with 1 to 16 carbon atom(s);

-   -   maleate esters, wherein the specific monomer can include:

wherein each of R₅ and R₆ is alkyl group with 1 to 16 carbon atom(s);

-   -   acrylic acid; methacrylic acid; maleic acid; maleic anhydride;        fumaric acid; crotonic acid; itaconic acid; acrylonitrile;        methylacrylonitrile; sodium vinylsulfonate; sodium vinyl        benzenesulfonate; mono-sodium        2-methyl-2-[(1-oxo-2-propenyl)amino]-1-propylsulfonate;        methacrylate ethyl trimethyl ammonium chloride; acrylamide;        hydroxymethylacrylamide; hydroxyethylacrylamide;        hydroxypropylacrylamide; vinyltrimethoxysilane;        vinyltriethoxysilane; vinyltri(2-methoxyethoxy)silane;        methylacryloxypropyltrimethoxysilane; ethylene glycol acrylate;        propylene glycol acrylate; glycidyl acrylate; diallyl maleate;        diallyl phthalate; triallyl cyanurate; allyl methacrylate;        ethylene glycol dimethylacrylate; pentaerythritol triacrylate;        pentaerythritol tetraacrylate; ethyl        acetoacetoxylmethylacrylate; diacetone acrylamide; allyl        acrylamide; or mixtures thereof.

In some non-limiting embodiments of the present invention, saidsurfactant can be selected from anionic surfactants, nonionicsurfactants or combination thereof.

Examples of anionic surfactants suitable for the present inventioninclude, but not limited to: alkylsulfates, alkylsulfonates, alkylbenzenesulfonates, alkyl polyoxyethylene ether sulfates,alkylpolyoxyethylene-propylene ether sulfates, sodium fatty alcoholsuccinic acid mono ester sulfonates, disodium fatty alcoholpolyoxyethylene ether sulfosuccinates, disodium fatty alcoholpolyoxyethylene-propylene ether sulfosuccinates, alkylpolyoxyethylenephosphates, alkylpolyoxyethylene-propylene phosphates and alkali metalsalts of fatty acids. Specific examples of anionic surfactants suitablefor the present invention include, but not limited to: sodiumdodecylbenzene sulfonate, sodium dodecylsulfonate, sodiumdodecylsulfate, disodium dodecyldiphenylether sulfonate, octadecylsulfosuccinic acid and sodium dioctylsulfosuccinate. In somenon-limiting embodiments of the present invention, the anionicsurfactants as mentioned above can be used in the form of aqueoussolution.

Examples of nonionic surfactants suitable for the present inventioninclude, but not limited to: linear alkyl alcohol polyoxyethyleneethers, linear alkyl alcohol polyoxyethylene-propylene ethers, branchedalkyl alcohol polyoxyethylene ethers, branched alkyl alcoholpolyoxyethylene-propylene ethers, fatty acid polyoxyethylenemonoesters,fatty acid polyoxyethylene-propylenemonoesters. Specific examples ofnonionic surfactants suitable for the present invention include, but notlimited to: isometric tridecyl alcohol polyoxyethylene monoether, cetylalcohol polyoxyethylenemonoether, octadecyl alcoholpolyoxyethylenemonoether lauroylhydroxylpolyoxyethylene, etc., whereinthe EO numbers of polyoxyethylene section are chosen according to thedesired HLB value of the surfactant, typically in the range of about 20to 40. In some non-limiting embodiments of the present invention, thenonionic surfactants as mentioned above can be used in the form ofaqueous solution.

In some non-limiting embodiments of the present invention, thesurfactant can be used in an amount of about 1-5 pphm, preferably about2-5 pphm, more preferably about 2-4 pphm.

In some non-limiting embodiments of the present invention, the polymericprotective colloid can be selected from partially hydrolyzed polyvinylalcohols, cellulose ethers and polyvinyl pyrrolidone. Specific examplesof polymeric protective colloids suitable for the present inventioninclude, but not limited to: polyvinyl alcohols having a degree ofalcoholysis of about 75 to 95%, more preferably about 70 to 92% and adegree of polymerization of about 200 to 4000, more preferably polyvinylalcohols having a degree of alcoholysis of about 80 to 90% and a degreeof polymerization of about 200 to 4000. Cellulose ethers as polymericprotective colloid suitable for the present invention include, but notlimited to, hydroxymethyl cellulose ether, hydroxyl ethylcellulose etherand hydroxypropyl cellulose ether. In some non-limiting embodiments ofthe present invention, the polymeric protective colloid can be used inan amount of about 0-10 pphm, preferably about 0-5 pphm.

According to one aspect of the present invention, a low odor papercoating composition, comprising a solid component and a binder,characterized in that said binder comprises:

-   (a) a vinyl acetate-ethylene copolymer-based emulsion, wherein the    copolymer comprises, based on the total weight of the copolymer:-   (1) about 65-95 pphm, preferably about 75-90 pphm of a moiety    derived from vinyl acetate;-   (2) about 5-35 pphm, preferably about 10-20 pphm of a moiety derived    from ethylene; and-   (3) about 0-10 pphm, preferably about 0-5 pphm of a moiety derived    from other comonomers or functional monomers,    wherein the copolymer-based emulsion is formed by emulsion    polymerization of the monomers in the presence of about 1-5 pphm,    preferably about 2-5 pphm, more preferably about 2-4 pphm of a    surfactant and about 0-10 pphm, preferably about 0-5 pphm of a    polymeric protective colloid as emulsifier/protective colloid,-   (b) additional water.

The low odor paper coating composition comprises the solid component andthe binder. In some non-limiting embodiments of the present invention,the weight ratio of solid component to binder is about 100:6 to 100:19,preferably about 100:8 to 100:16.

The solid component used in low odor paper coating composition cancomprise, but not limited to, kaolin, calcium carbonate or a mixturethereof.

The binder used in low odor paper coating composition comprises mainlyvinyl acetate-ethylene copolymer-based emulsion and additional water. Insome non-limiting embodiments of the present invention, the binder canhave a solid content of about 40 to 70%, more commonly about 50 to 60%by weight.

In some non-limiting embodiments of the present invention, the binderused in low odor paper coating composition essentially consists of vinylacetate-ethylene copolymer-based emulsion, additional water and otherconventional additives.

The conventional additives added to the aqueous phase of the binder mayinclude those known in the art which are useful in the emulsionpolymerization system or improve the stability or pot life of the finalemulsion. For example, those additives can be redox reaction promoter,pH adjusting agents, ion intensity regulators, molecular weightmodifiers, defoamers, fungicides, chelating agents, and the like.

In some non-limiting embodiments of the present invention, the emulsionpolymerization is conducted in the presence of a redox initiator. Theoxidizing agent and reducing agent used to make up of the redoxinitiator include, but not limited to water soluble oxidizing agents andreducing agents known in the art. Examples of oxidizing agents andreducing agents suitable for the present invention may include, but notlimited to, ammonium persulfate, sodium persulfate, hydrogen peroxide,tert-butyl peroxide, sodium formaldehyde-sulfoxylate, disodium2-hydroxyl-2-sulfinatoacetate, ascorbic acid, erythorbic acid, alkalimetal salts of ascorbic acid, alkali metal salts of erythorbic acid,sodium bisulfite, sodium sulfite, sodium metabisulfite, sodiumthiosulfate, etc. Typically, the oxidizing agent and reducing agent canbe each added in an amount of about 0.05 to 5 pphm.

According to another aspect of the present invention, a process forpreparing the vinyl acetate-ethylene copolymer-based emulsion isprovided. Said process comprises emulsion polymerizing a monomericcomposition comprising:

-   -   (1) about 65-95 pphm of a moiety derived from vinyl acetate;    -   (2) about 5-35 pphm of a moiety derived from ethylene; and    -   (3) about 0-10 pphm of a moiety derived from other comonomers or        functional monomers,        in the presence of about 1-5 pphm, preferably about 2-5 pphm,        more preferably about 2-4 pphm of a surfactant and about 0-10        pphm, preferably about 0-5 pphm of a polymeric protective        colloid as emulsifier/protective colloid.

According to another aspect of the present invention, a process forpreparing the low odor paper coating composition is provided, saidprocess comprises

-   (a) forming an ethylene-vinyl acetate copolymer-based emulsion by    emulsion polymerizing a monomeric composition comprising:    -   (1) about 65-95 pphm of a moiety derived from vinyl acetate;    -   (2) about 5-35 pphm of a moiety derived from ethylene; and    -   (3) about 0-10 pphm of a moiety derived from other comonomers or        functional monomers,        in the presence of about 1-5 pphm, preferably about 2-5 pphm,        more preferably about 2-4 pphm of a surfactant and about 0-10        pphm, preferably about 0-5 pphm of a polymeric protective        colloid as emulsifier/protective colloid;-   (b) mixing said ethylene-vinyl acetate copolymer-based emulsion with    additional water to form a binder;-   (c) mixing said binder with a solid component.

In a preferable embodiment of the present invention, the emulsion may beobtained by the following steps: forming an aqueous phase by addingsurfactant and protective colloid, as emulsifier, and other additivessuch as defoamers, pH adjusting agents, ion intensity regulators,molecular weight modifiers, etc. into water under stirring; feeding theaqueous phase to a reactor under slow stirring; evacuating the reactorunder vacuum and purging with nitrogen several times for removing anyair; raising the temperature of the reactor to about 40-70° C., thenincreasing the speed of stirring, adding to the reactor part of thevinyl acetate monomer or mixture of the vinyl acetate monomer and theother comonomers or functional monomers, together with part of ethylenegas; after the temperature and pressure of the reactor becomes stable,adding dropwise oxidizing agent and reducing agent, as polymerizationinitiator, so that polymerization takes place, with increasing oftemperature; adding remaining monomers when the temperature of thereactor reaches a predetermined value, about 50-90° C., until theconsumption of the monomers. The temperature of the reactor wascontrolled at about 50-90° C. during the emulsion polymerizationprocess. After completion of polymerization, the reactor is cooled toselected temperature, about 50-70° C., and the polymerization producttherein was transferred to a post-treatment reactor, while the unreactedethylene gas was discharged as exhaust gas. Subsequently, certain amountof oxidizing agent and reducing agent were added to the post-treatmentreactor, to reduce the amount of residual monomers by further initiatingthe polymerization of residual monomers. Alternatively, the amount ofresidual monomers can be further reduced by extraction of water vapor.Finally, the emulsion parameters of the copolymer-based emulsion thusobtained can be adjusted by feeding with additional water and/or otherconventional additives, such as fungicides, pH adjusting agents, etc.The emulsion thus obtained can have a solid content of about 40 to 70%,most commonly about 50 to 60% by weight, and can be used as binder forthe low odor paper coating composition according to the presentinvention.

In some non-limiting embodiments of the present invention, a vinylacetate-ethylene copolymer-based emulsion was obtained according to theabove mentioned formulation and process, and the vinyl acetate-ethylenecopolymer-based emulsion thus obtained can be used to formulate the lowodor paper coating composition.

In a preferable embodiment of the present invention, the low odor papercoating composition may be obtained by the following steps: forming anslurry by mixing the solid component with water, dispersing agents,defoamers and the like; the slurry thus obtained is added with thebinder derived from the vinyl acetate-ethylene copolymer-based emulsionand co-adjuvants such as fluorescent whiteners, rheology modifiers,etc., and mixed under stirring to obtain a homogeneous paper coatingcomposition.

In some non-limiting embodiments of the present invention, the low odorpaper coating composition according to the present invention comprises:

-   100 parts of solid component, which comprises kaolin, calcium    carbonate or a mixture thereof;    -   about 6-19 parts, preferably about 8-16 parts of binder;    -   about 0.05-1 part, preferably about 0.1-0.5 part of dispersing        agents, suitable examples of which may include, but not limited        to: acrylate dispersing agents, such as sodium acrylate,        ammonium acrylate, potassium acrylate, etc.; polyphosphate        dispersing agents, such as sodium tripolyphosphate, tetrasodium        pyrophosphate, sodium hexametaphosphate, etc.; sulfonate        dispersing agents, such as lignin sulfonate, aromatic sulfonate,        aliphatic sulfonate, sodium succinsulfonate, etc.; or mixtures        thereof;    -   about 0.05-0.5 part, preferably about 0.1-0.3 part of defoamers,        suitable examples of which may include, but not limited to:        polyol defoamers, polyether defoamers, mineral oil defoamers,        silicone defoamers, or mixtures thereof;    -   about 0.05-1 part, preferably about 0.1-0.4 part of rheology        modifiers, suitable examples of which may include, but not        limited to: associative rheology modifiers, alkali swelling        rheology modifiers, cellulosic rheology modifiers, natural        polymer rheological modifiers and the like, such as polyurethane        thickeners, sodium acrylate thickeners, acrylate thickeners,        carboxymethyl cellulose, hydroxyethyl cellulose,        hydroxypropylmethyl cellulose, carrageenin, agar, sodium        alginate, etc.; or mixtures thereof;    -   about 0-0.8 part, preferably about 0.3-0.6 part of fluorescent        whiteners, suitable examples of which may include, but not        limited to: diaminodistyrenedisulfonate,        diaminodistyrenetetrasulfonate, and        diaminodistyrenehexasulfonate, or mixtures thereof;    -   about 0.1-0.4 part of pH adjusting agents, which is used to keep        the pH value of the paper coating composition between 8 to 11,        suitable examples of which may include, but not limited to:        sodium hydroxide, potassium hydroxide, ammonia and organic amine        modifiers, or mixtures thereof.

According to the concept of the present invention, the present inventioncomprises the following items:

1. A low odor paper coating composition, comprising a solid componentand a binder, characterized in that said binder comprises:

-   (a) a vinyl acetate-ethylene copolymer-based emulsion, wherein the    copolymer comprises, based on the total weight of the copolymer:    -   (1) about 65-95 pphm of a moiety derived from vinyl acetate;    -   (2) about 5-35 pphm of a moiety derived from ethylene; and    -   (3) about 0-10 pphm of a moiety derived from other comonomers or        functional monomers,        wherein the copolymer-based emulsion is formed by emulsion        polymerization of the monomers in the presence of about 1-5        pphm, preferably about 2-5 pphm, more preferably about 2-4 pphm        of a surfactant and about 0-10 pphm, preferably about 0-5 pphm        of a polymeric protective colloid as emulsifier/protective        colloid,-   (b) additional water.-   2. The paper coating composition according to any of the preceding    items, wherein the surfactant is selected from anionic surfactants,    nonionic surfactants or combination thereof.-   3. The paper coating composition according to any of the preceding    items, wherein the anionic surfactants are selected from    alkylsulfates, alkylsulfonates, alkyl benzenesulfonates, alkyl    polyoxyethylene ether sulfates, alkylpolyoxyethylene-propylene ether    sulfates, sodium fatty alcohol succinic acid mono ester sulfonates,    disodium fatty alcohol polyoxyethylene ether sulfosuccinates,    disodium fatty alcohol polyoxyethylene-propylene ether    sulfosuccinates, alkylpolyoxyethylene phosphates,    alkylpolyoxyethylene-propylene phosphates, alkali metal salts of    fatty acids, or mixtures thereof.-   4. The paper coating composition according to any of the preceding    items, wherein the nonionic surfactants are selected from linear    alkyl alcohol polyoxyethylene ethers, linear alkyl alcohol    polyoxyethylene-propylene ethers, branched alkyl alcohol    polyoxyethylene ethers, branched alkyl alcohol    polyoxyethylene-propylene ethers, fatty acid    polyoxyethylenemonoesters, fatty acid    polyoxyethylene-propylenemonoesters, or mixtures thereof.-   5. The paper coating composition according to any of the preceding    items, wherein the polymeric protective colloid is selected from    partially hydrolyzed polyvinyl alcohols, cellulose ethers, polyvinyl    pyrrolidone, or mixtures thereof.-   6. The paper coating composition according to any of the preceding    items, wherein the polyvinyl alcohol has a degree of alcoholysis of    about 75 to 95%, more preferably about 70 to 92% and a degree of    polymerization of about 200 to 4000, preferably a degree of    alcoholysis of about 80 to 90% and a degree of polymerization of    about 200 to 4000.-   7. The paper coating composition according to any of the preceding    items, wherein other comonomers or functional monomers are selected    from:    -   vinyl esters of polyacid, wherein the specific monomer can        include:

wherein each of R₁ and R₂ is hydrogen or alkyl group, provided that thetotal carbon atom number of R₁ and R₂ is from 1 to 14;

-   -   acrylates, wherein the specific monomer can include:

wherein R₃ is hydrogen or alkyl group with 1 to 16 carbon atom(s);

-   -   methacrylates, wherein the specific monomer can include:

wherein R₄ is hydrogen or alkyl group with 1 to 16 carbon atom(s);

-   -   maleate esters, wherein the specific monomer can include:

wherein each of R₅ and R₆ is alkyl group with 1 to 16 carbon atom(s);

-   -   acrylic acid; methacrylic acid; maleic acid; maleic anhydride;        fumaric acid; crotonic acid; itaconic acid; acrylonitrile;        methylacrylonitrile; sodium vinylsulfonate; sodium vinyl        benzenesulfonate; mono-sodium        2-methyl-2-[(1-oxo-2-propenyl)amino]-1-propylsulfonate;        methacrylate ethyl trimethyl ammonium chloride; acrylamide;        hydroxymethylacrylamide; hydroxyethylacrylamide;        hydroxypropylacrylamide; vinyltrimethoxysilane;        vinyltriethoxysilane; vinyltri(2-methoxyethoxy)silane;        methylacryloxypropyltrimethoxysilane; ethylene glycol acrylate;        propylene glycol acrylate; glycidyl acrylate; diallyl maleate;        diallyl phthalate; triallyl cyanurate; allyl methacrylate;        ethylene glycol dimethylacrylate; pentaerythritol triacrylate;        pentaerythritol tetraacrylate; ethyl        acetoacetoxylmethylacrylate; diacetone acrylamide; allyl        acrylamide; or mixtures thereof.

-   8. The paper coating composition according to any of the preceding    items, wherein the solid component comprises kaolin, calcium    carbonate or a mixture thereof.

-   9. The paper coating composition according to any of the preceding    items, wherein the weight ratio of solid component to binder is bout    100:6 to 100:19, preferably about 100:8 to 100:16.

-   10. The paper coating composition according to any of the preceding    items, wherein the content of residue vinyl acetate monomer is less    than about 800 ppm, preferably less than about 600 ppm, more    preferably less than about 400 ppm.

-   11. A process for preparing the low odor paper coating composition    according to any of the preceding items, said process comprises

-   (a) forming an ethylene-vinyl acetate copolymer-based emulsion by    emulsion polymerizing a monomeric composition comprising:    -   (1) about 65-95 pphm of a moiety derived from vinyl acetate;    -   (2) about 5-35 pphm of a moiety derived from ethylene; and    -   (3) about 0-10 pphm of a moiety derived from other comonomers or        functional monomers,        in the presence of about 1-5 pphm, preferably about 2-5 pphm,        more preferably about 2-4 pphm of a surfactant and about 0-10        pphm, preferably about 0-5 pphm of a polymeric protective        colloid as emulsifier/protective colloid;

-   (b) mixing said ethylene-vinyl acetate copolymer-based emulsion with    additional water to form a binder;

-   (c) mixing said binder with a solid component.

-   12. A vinyl acetate-ethylene copolymer-based emulsion for low odor    paper coating composition, wherein the copolymer comprises, based on    the total weight of the copolymer:    -   (1) about 65-95 pphm of a moiety derived from vinyl acetate;    -   (2) about 5-35 pphm of a moiety derived from ethylene; and    -   (3) about 0-10 pphm of a moiety derived from other comonomers or        functional monomers,        wherein the copolymer-based emulsion is formed by emulsion        polymerization of the monomers in the presence of about 1-5        pphm, preferably about 2-5 pphm, more preferably about 2-4 pphm        of a surfactant and about 0-10 pphm, preferably about 0-5 pphm        of a polymeric protective colloid as emulsifier/protective        colloid.

-   13. The vinyl acetate-ethylene copolymer-based emulsion according to    any of the preceding items, wherein the surfactant is selected from    anionic surfactants, nonionic surfactants or combination thereof.

-   14. The vinyl acetate-ethylene copolymer-based emulsion according to    any of the preceding items, wherein the anionic surfactants are    selected from alkylsulfates, alkylsulfonates, alkyl    benzenesulfonates, alkyl polyoxyethylene ether sulfates,    alkylpolyoxyethylene-propylene ether sulfates, sodium fatty alcohol    succinic acid mono ester sulfonates, disodium fatty alcohol    polyoxyethylene ether sulfosuccinates, disodium fatty alcohol    polyoxyethylene-propylene ether sulfosuccinates,    alkylpolyoxyethylene phosphates, alkylpolyoxyethylene-propylene    phosphates, alkali metal salts of fatty acids, or mixtures thereof.

-   15. The vinyl acetate-ethylene copolymer-based emulsion according to    any of the preceding items, wherein the nonionic surfactants are    selected from linear alkyl alcohol polyoxyethylene ethers, linear    alkyl alcohol polyoxyethylene-propylene ethers, branched alkyl    alcohol polyoxyethylene ethers, branched alkyl alcohol    polyoxyethylene-propylene ethers, fatty acid    polyoxyethylenemonoesters, fatty acid    polyoxyethylene-propylenemonoesters, or mixtures thereof.

-   16. The vinyl acetate-ethylene copolymer-based emulsion according to    any of the preceding items, wherein the polymeric protective colloid    is selected from partially hydrolyzed polyvinyl alcohols, cellulose    ethers, polyvinyl pyrrolidone, or mixtures thereof.

-   17. The vinyl acetate-ethylene copolymer-based emulsion according to    any of the preceding items, wherein the polyvinyl alcohol has a    degree of alcoholysis of about 75 to 95%, more preferably about 70    to 92% and a degree of polymerization of about 200 to 4000,    preferably a degree of alcoholysis of about 80 to 90% and a degree    of polymerization of about 200 to 4000.

-   18. The vinyl acetate-ethylene copolymer-based emulsion according to    any of the preceding items, wherein other comonomers or functional    monomers are selected from:    -   vinyl esters of polyacid, wherein the specific monomer can        include:

wherein each of R₁ and R₂ is hydrogen or alkyl group, provided that thetotal carbon atom number of R₁ and R₂ is from 1 to 14;

-   -   acrylates, wherein the specific monomer can include:

wherein R₃ is hydrogen or alkyl group with 1 to 16 carbon atom(s);

-   -   methacrylates, wherein the specific monomer can include:

wherein R₄ is hydrogen or alkyl group with 1 to 16 carbon atom(s);

-   -   maleate esters, wherein the specific monomer can include:

wherein each of R₅ and R₆ is alkyl group with 1 to 16 carbon atom(s);

-   -   acrylic acid; methacrylic acid; maleic acid; maleic anhydride;        fumaric acid; crotonic acid; itaconic acid; acrylonitrile;        methylacrylonitrile; sodium vinylsulfonate; sodium vinyl        benzenesulfonate; mono-sodium        2-methyl-2-[(1-oxo-2-propenyl)amino]-propylsulfonate;        methacrylate ethyl trimethyl ammonium chloride; acrylamide;        hydroxymethylacrylamide; hydroxyethylacrylamide;        hydroxypropylacrylamide; vinyltrimethoxysilane;        vinyltriethoxysilane; vinyltri(2-methoxyethoxy)silane;        methylacryloxypropyltrimethoxysilane; ethylene glycol acrylate;        propylene glycol acrylate; glycidyl acrylate; diallyl maleate;        diallyl phthalate; triallyl cyanurate; allyl methacrylate;        ethylene glycol dimethylacrylate; pentaerythritol triacrylate;        pentaerythritol tetraacrylate; ethyl        acetoacetoxylmethylacrylate; diacetone acrylamide; allyl        acrylamide; or mixtures thereof.

-   19. The vinyl acetate-ethylene copolymer-based emulsion according to    any of the preceding items, wherein the copolymer-based emulsion has    a solid content of about 40 to 70%, most commonly about 50 to 60% by    weight based on the total weight of the emulsion.

-   20. The vinyl acetate-ethylene copolymer-based emulsion according to    any of the preceding items, wherein the content of residue vinyl    acetate monomer is less than about 800 ppm, preferably less than    about 600 ppm, more preferably less than about 400 ppm.

-   21. A process for preparing the vinyl acetate-ethylene    copolymer-based emulsion according to any of the preceding items,    said process comprises emulsion polymerizing a monomeric composition    comprising:    -   (1) about 65-95 pphm of a moiety derived from vinyl acetate;    -   (2) about 5-35 pphm of a moiety derived from ethylene; and    -   (3) about 0-10 pphm of a moiety derived from other comonomers or        functional monomers,        in the presence of about 1-5 pphm, preferably about 2-5 pphm,        more preferably about 2-4 pphm of a surfactant and about 0-10        pphm, preferably about 0-5 pphm of a polymeric protective        colloid as emulsifier/protective colloid.

-   22. The process according to any of the preceding items, wherein the    emulsion polymerization is carried out in the presence of a redox    initiator.

-   23. The process according to any of the preceding items, wherein the    initiator is selected from ammonium persulfate, sodium persulfate,    hydrogen peroxide, tert-butyl peroxide, sodium    formaldehyde-sulfoxylate, disodium 2-hydroxyl-2-sulfinatoacetate,    ascorbic acid, erythorbic acid, alkali metal salts of ascorbic acid,    alkali metal salts of erythorbic acid, sodium bisulfite, sodium    sulfite, sodium metabisulfite, sodium thiosulfate, or mixtures    thereof.

-   24. Use of the vinyl acetate-ethylene copolymer-based emulsion    according to any of the preceding items or obtainable by the process    according to any of the preceding items in low odor paper coating    composition.

-   25. Use of the low odor paper coating composition according to any    of the preceding items in high end packaging application, such as    cigarette package and food package.

The inventive paper coating composition has extraordinary low odor, evenafter application of Ultra-Violet (UV) curable ink and electron beamradiation curable ink printing techniques. In the context of thisapplication, the term “low odor” means that the inventive paper coatingcomposition pass the odor evaluation test as described hereinafter.

The odor evaluation test can be carried out as follows:

-   1. Preparation of paper sample.-   A paper sample is prepared by the following steps: the binder    derived from vinyl acetate-ethylene copolymer-based emulsion    produced by aqueous emulsion polymerization as described above is    mixed with solid component, dispersing agents, fluorescent whiteners    and rheology modifiers to obtain a paper coating composition; the    paper coating composition thus obtained is applied to both sides of    a raw paper in an amount of 10-15 gsm/10-15 gsm/10-15 gsm for    pre-coating/middle coating/top-coating; the coated white paperboard    is calendered through a calender and sealed inside a plastic bag for    storing.-   2. UV curing-   The paper sample thus obtained is withdrawn from the plastic bag,    curable in a UV drier, and then sealed again inside a plastic bag    for storing. The parameters used in UV radiation are: UV lamp, 6wx4;    wavelength, 254 nm; radiation time, 30 min.-   3. Odor evaluation-   The odor evaluation is carried out in 12 hours after UV curing. The    odor evaluation procedures are as follows: a sealed plastic bag    containing the paper sample is placed in front of the nose of an    evaluator and then opened; the evaluator breathes in the air    released from the plastic bag immediately after the plastic bag is    opened, and scores the smell by a value ranging from 1 to 5, with    the value of 1 represents the highest odor and the worst score, and    the value of 5 represents the lowest odor and the best score. Each    paper sample is evaluated by ten random selected persons    respectively and the sum of the scores is output as the final result    for each paper sample. The sum of the scores of each paper sample is    compared with those of other paper samples, whereby a final score    evaluation to each paper sample is obtained. Typically, a value of 5    represents the lowest odor which cannot be obviously smelled by the    evaluator, a value of 1 represents the highest odor, which means    that the tested sample exhibits severe sour smell, bitter smell or    other chemical's smell to the evaluator, while a value ranging from    4 to 2 represents a slight odor, obvious odor or heavier odor    sequentially.

In some non-limiting embodiments of the present invention, the inventivelow odor paper coating composition made from vinyl acetate-ethylenecopolymer-based emulsion produce by aqueous emulsion polymerization asdescribed above exhibits a final score of greater than 30, morepreferably greater than 40 when compared with other paper coatingcomposition made from traditional aqueous emulsions, such asstyrene-butadiene copolymer emulsion, styrene-acrylate copolymeremulsion, acrylate copolymer emulsion, vinyl acetate homopolymeremulsion, vinyl acetate-ethylene copolymer emulsion, etc.

The following Examples are included to demonstrate preferred embodimentsof the invention. It should be appreciated by those of skill in the artthat the techniques disclosed in the Examples which follow representtechniques discovered by the inventor to function well in the practiceof the invention, and thus can be considered to constitute preferredmodes for its practice. However, those of skill in the art should, inlight of the present disclosure, appreciate that many changes can bemade in the specific embodiments which are disclosed and still obtain alike or similar result without departing from the spirit and scope ofthe invention.

EXAMPLES

Unless indicated to the contrary, all parts and percentages are byweight.

Test

The odor of the inventive paper coating composition and othercomparative paper coating compositions are tested according to the odorevaluation test as described above.

Example 1

To a 10 L reactor was added 2.4 kg deionized water, 116 g polyvinylalcohol having an alcoholysis degree of 88% and a viscosity of 5 mPa·sin 4% aqueous solution at 20° C. and 120 g polyvinyl alcohol having analcoholysis degree of 88% and a viscosity of 23 mPa·s in 4% aqueoussolution at 20° C. with stirring (300 rpm). The reactor was heated to99° C. and maintained for 1 hour to obtain a sufficiently dissolvedsolution. The reactor was then cooled to 55° C. 33 g Disponil A3065(Cognis, with a concentration of 65%), 3 g sodium acetate and 6 g 85%phosphoric acid solution (which were used to adjust the pH of thesolution), 2 g silicone defoamer and 0.2 g 40% ferric chloride solutionwere added sequentially into the reactore to provide a catalyst for thepolymerization reaction. The reactor was evacuated and purged withnitrogen for three times to remove residual air. The stirring speed wasthen increased to 600 rpm. 2.9 kg vinyl acetates were added into thereactor by feeding pump, and 550 g ethylene gases were fed into thereactor at the same time. The pressure of the reactor was equilibratedfor 5 mins, and then the reactor was charged with 35 g of 1.7 wt %aqueous solution of disodium 2-hydroxy-2-sulfinatoacetate. The reactorwas kept under 55° C. and equilibrated for 5 mins. The polymerizationreaction was initiated by feeding into the reactor with the followinginitiators: 1.5 wt % aqueous solution of t-butyl peroxide with astarting feeding rate of 94.5 g/h, 1.7 wt % aqueous solution of disodium2-hydroxy-2-sulfinatoacetate with a starting feeding rate of 94.5 g/h.When the temperature of the reactor reached 57° C., the reactiontemperature was controlled by adjusting the flow rates of the initiatorsso that the reaction temperature increased to 85° C. in 20 mins and thenwas maintained under 85° C. When temperature of the reactor reached 72°C., 230 g ethylene gases were added, and the maximum pressure inside thereactor was maintained below 60bar. When temperature of the reactorreached 80° C., 1.24 kg vinyl acetates were added into the reactor witha feeding rate of 1.26 kg/h.

After completion of adding the initiators, the reactor was cooled to 55°C. The obtained emulsion was transferred to post-treatment reactor.

The post-treatment reactor was stirred at a speed of 200 rpm and chargedwith 90 g of 3.1 wt % aqueous solution of disodium2-hydroxy-2-sulfinatoacetate in 30 mins, then 90 g of mixture of 1 wt %aqueous solution of t-butyl peroxide and 1 wt % aqueous solution ofhydrogen peroxide in 30 mins. The post-treatment reactor was kept undera vacuum degree of −0.3 bar. When the temperature of the post-treatmentreactor reached 65° C., a total amount of 105 g water vapor was chargedin to the post-treatment reactor for extraction. Finally, thepost-treatment reactor was cooled to 40° C. 30 g 1.5% CIT/MIT fungicideswere added into the post-treatment reactor.

The properties of the obtained vinyl acetate-ethylene copolymer-basedemulsion (Emulsion 1) are listed in Table 1.

TABLE 1 Properties of Emulsion 1 solid content 56.42% by weight pH 4.3viscosity (BVF, 20 rpm) 5670 mPa · s particle size (D90) 2.0 μm ResidualMonomers 291 ppm

Example 2

A vinyl acetate-ethylene copolymer-based emulsion (Emulsion 2) wasprepared according to the procedure in Example 1, except that thepost-treatment reactor has not subjected to water vapor extraction. Theobtained vinyl acetate-ethylene copolymer-based emulsion (Emulsion 2)has a residual monomer content of 685 ppm.

Comparative Example 1

A commercial available styrene-butadiene copolymer emulsion (ComparativeEmulsion 1) for paper coating was obtained, which has a residual monomercontent of 60 ppm.

Comparative Example 2

A commercial available styrene-acrylate copolymer emulsion (ComparativeEmulsion 2) for paper coating was obtained, which has a residual monomercontent of 550 ppm.

Results and Discussion

The emulsions as obtained in Example 1-2 and Comparative Example 1-2were used to prepare paper coating compositions respectively accordingto the formulation as listed in Table 2.

TABLE 2 Formulation of the paper coating compositions Component Amount,parts by weight Emulsion, on dry basis 14 Kaolin 30 Calcium carbonateC95 70 Dispersing agent 5040 0.1 Fluorescent whitener OBA 0.75 ThickenerCMC 0.4 Defoamer Foamaster NXZ 0.1 Sodium hydroxide 0.1

The paper coating compositions thus obtained were tested according tothe odor evaluation test as described above respectively and the resultsare summarized in Table 3.

TABLE 3 Results of odor evaluation test Residual Monomer Content ofemulsion, Score of the odor ppm evaluation test Paper coatingcomposition 291 41 prepared from Emulsion 1 Paper coating composition685 34 prepared from Emulsion 2 Ppaper coating composition 60 24prepared from Comparative Emulsion 1 Ppaper coating composition 550 27prepared from Comparative Emulsion 2

According to results of Table 3, although the residual monomer contentof Emulsion 1 (291 ppm) is higher than that of Comparative Emulsion 1(60 ppm), the paper coating composition prepared from Emulsion 1according to the present invention exhibits a much higher score thanthat of the paper coating composition prepared from ComparativeEmulsion 1. The paper coating composition prepared from Emulsion 2 witha high residual monomer content of 685 ppm also passes the odorevaluation test with a value of greater than 30, which suggests that thevinyl acetate-ethylene copolymer-based emulsion according to the presentinvention can provide low odor to the paper coating composition preparedtherefrom, especially after exposure to UV drier according to theprocedure of odor evaluation test, therefore is useful as binder forprinting packages with high qualities, such as cigarette package, foodpackage and the like.

All of the methods disclosed and claimed herein can be made and executedwithout undue experimentation in light of the present disclosure. Whilethe products and methods of this invention have been described in termsof preferred embodiments, it will be apparent to those of skill in theart that variations may be applied to the methods and in the steps or inthe sequence of steps of the method described herein without departingfrom the concept, spirit and scope of the invention.

1. A low odor paper coating composition, comprising a solid componentand a binder, characterized in that said binder comprises: (a) a vinylacetate-ethylene copolymer-based emulsion, wherein the copolymercomprises, based on the total weight of the copolymer: (1) about 65-95pphm of a moiety derived from vinyl acetate; (2) about 5-35 pphm of amoiety derived from ethylene; and (3) about 0-10 pphm of a moietyderived from other comonomers or functional monomers, wherein thecopolymer-based emulsion is formed by emulsion polymerization of themonomers in the presence of about 1-5 pphm of a surfactant and about0-10 pphm of a polymeric protective colloid as emulsifier/protectivecolloid, (b) additional water.
 2. The paper coating compositionaccording to claim 1, wherein the surfactant is selected from anionicsurfactants, nonionic surfactants or combination thereof.
 3. The papercoating composition according to claim 2, wherein the anionicsurfactants are selected from alkylsulfates, alkylsulfonates, alkylbenzenesulfonates, alkyl polyoxyethylene ether sulfates,alkylpolyoxyethylene-propylene ether sulfates, sodium fatty alcoholsuccinic acid mono ester sulfonates, disodium fatty alcoholpolyoxyethylene ether sulfosuccinates, disodium fatty alcoholpolyoxyethylene-propylene ether sulfosuccinates, alkylpolyoxyethylenephosphates, alkylpolyoxyethylene-propylene phosphates, alkali metalsalts of fatty acids, or mixtures thereof.
 4. The paper coatingcomposition according to claim 2, wherein the nonionic surfactants areselected from linear alkyl alcohol polyoxyethylene ethers, linear alkylalcohol polyoxyethylene-propylene ethers, branched alkyl alcoholpolyoxyethylene ethers, branched alkyl alcohol polyoxyethylene-propyleneethers, fatty acid polyoxyethylenemonoesters, fatty acidpolyoxyethylene-propylenemonoesters, or mixtures thereof.
 5. The papercoating composition according to claim 1, wherein the polymericprotective colloid is selected from partially hydrolyzed polyvinylalcohols, cellulose ethers, polyvinyl pyrrolidone, or mixtures thereof.6. The paper coating composition according to claim 5, wherein thepolyvinyl alcohol has a degree of alcoholysis of about 75 to 95% and adegree of polymerization of about 200 to
 4000. 7. The paper coatingcomposition according to claim 1, wherein other comonomers or functionalmonomers are selected from: vinyl esters of polyacid, wherein thespecific monomer can include:

wherein each of R₁ and R₂ is hydrogen or alkyl provided that the totalcarbon atom number of R₁ and R₂ is from 1 to 14; acrylates, wherein thespecific monomer can include:

wherein R₃ is hydrogen or alkyl group with 1 to 16 carbon atom(s);methacrylates, wherein the specific monomer can include:

wherein R is hydrogen or alkyl group with 1 to 16 carbon atom(s);maleate esters, wherein the specific monomer can include:

wherein each of R₅ and R₆ is alkyl group with 1 to 16 carbon atom(s);acrylic acid; methacrylic acid; maleic acid; maleic anhydride; fumaricacid; crotonic acid; itaconic acid; acrylonitrile; methylacrylonitrile;sodium vinylsulfonate; sodium vinyl benzenesulfonate; mono-sodium2-methyl-2-[(1-oxo-2-propenyl)amino]-1-propylsulfonate; methacrylateethyl trimethyl ammonium chloride; acrylamide; hydroxymethylacrylamide;hydroxyethylacrylamide; hydroxypropylacrylamide vinyltrimethoxysilane;vinyltriethoxysilane; vinyltri(2-methoxyethoxy)silane;methylacryloxypropyltrimethoxysilane; ethylene glycol acrylate;propylene glycol acrylate; glycidyl acrylate; diallyl maleate; diallylphthalate; triallyl cyanurate; allyl methacrylate; ethylene glycoldimethylacrylate; pentaerythritol triacrylate; pentaerythritoltetraacrylate; ethyl acetoacetoxylmethylacrylate; diacetone acrylamide;allyl acrylamide; or mixtures thereof.
 8. The paper coating compositionaccording to claim 1, wherein the solid component comprises kaolin,calcium carbonate or a mixture thereof.
 9. The paper coating compositionaccording to claim 1, wherein the weight ratio of solid component tobinder is bout 100:6 to 100:19, preferably about 100:8 to 100:16.
 10. Aprocess for preparing the low odor paper coating composition accordingto claim 1, said process comprises (a) forming an ethylene-vinyl acetatecopolymer-based emulsion by emulsion polymerizing a monomericcomposition comprising: (1) about 65-95 pphm of a moiety derived fromvinyl acetate; (2) about 5-35 pphm of a moiety derived from ethylene;and (3) about 0-10 pphm of a moiety derived from other comonomers orfunctional monomers, in the presence of about 1-5 pphm, of a surfactantand about 0-10 pphm of a polymeric protective colloid asemulsifier/protective colloid; (b) mixing said ethylene-vinyl acetatecopolymer-based emulsion with additional water to form a binder; (c)mixing said binder with a solid component.
 11. A vinyl acetate-ethylenecopolymer-based emulsion for low odor paper coating composition, whereinthe copolymer comprises, based on the total weight of the copolymer: (1)about 65-95 pphm of a moiety derived from vinyl acetate; (2) about 5-35pphm of a moiety derived from ethylene; and (3) about 0-10 pphm of amoiety derived from other comonomers or functional monomers, wherein thecopolymer-based emulsion is formed by emulsion polymerization of themonomers in the presence of about 1-5 pphm of a surfactant and about0-10 pphm of a polymeric protective colloid as emulsifier/protectivecolloid.
 12. The vinyl acetate-ethylene copolymer-based emulsionaccording to claim 11, wherein the surfactant is selected from anionicsurfactants, nonionic surfactants or combination thereof.
 13. The vinylacetate-ethylene copolymer-based emulsion according to claim 12, whereinthe anionic surfactants are selected from alkylsulfates,alkylsulfonates, alkyl benzenesulfonates, alkyl polyoxyethylene ethersulfates, alkylpolyoxyethylene-propylene ether sulfates, sodium fattyalcohol succinic acid mono ester sulfonates, disodium fatty alcoholpolyoxyethylene ether sulfosuccinates, disodium fatty alcoholpolyoxyethylene-propylene ether sulfosuccinates, alkylpolyoxyethylenephosphates, alkylpolyoxyethylene-propylene phosphates, alkali metalsalts of fatty acids, or mixtures thereof.
 14. The vinylacetate-ethylene copolymer-based emulsion according to claim 12, whereinthe nonionic surfactants are selected from linear alkyl alcoholpolyoxyethylene ethers, linear alkyl alcohol polyoxyethylene-propyleneethers, branched alkyl alcohol polyoxyethylene ethers, branched alkylalcohol polyoxyethylene-propylene ethers, fatty acidpolyoxyethylenemonoesters, fatty acidpolyoxyethylene-propylenemonoesters, or mixtures thereof.
 15. The vinylacetate-ethylene copolymer-based emulsion according to claim 11, whereinthe polymeric protective colloid is selected from partially hydrolyzedpolyvinyl alcohols, cellulose ethers, polyvinyl pyrrolidone, or mixturesthereof.
 16. The vinyl acetate-ethylene copolymer-based emulsionaccording to claim 15, wherein the polyvinyl alcohol has a degree ofalcoholysis of about 75 to 95% and a degree of polymerization of about200 to
 4000. 17. The vinyl acetate-ethylene copolymer-based emulsionaccording to claim 11, wherein other comonomers or functional monomersare selected from: vinyl esters of polyacid, wherein the specificmonomer can include:

wherein each of R₁ and R₂ is hydrogen or alkyl group, provided that thetotal carbon atom number of R₁ and R₂ is from 1 to 14; acrylates,wherein the specific monomer can include:

wherein R₃ is hydrogen or alkyl group with 1 to 16 carbon atom(s);methacrylates, wherein the specific monomer can include:

wherein R is hydrogen or alkyl group with 1 to 16 carbon atom(s);maleate esters, wherein the specific monomer can include:

wherein each of R₅ and R₆ is alkyl group with 1 to 16 carbon atom(s);acrylic acid; methacrylic acid; maleic acid; maleic anhydride; fumaricacid; crotonic acid; itaconic acid; acrylonitrile; methylacrylonitrile;sodium vinylsulfonate; sodium vinyl benzenesulfonate; mono-sodium2-methyl-2-[(1-oxo-2-propenyl)amino]-1-propylsulfonate; methacrylateethyl trimethyl ammonium chloride; acrylamide; hydroxymethylacrylamide;hydroxyethylacrylamide; hydroxypropylacrylamide vinyltrimethoxysilane;vinyltriethoxysilane; vinyltri(2-methoxyethoxy)silane;methylacryloxypropyltrimethoxysilane; ethylene glycol acrylate;propylene glycol acrylate; glycidyl acrylate; diallyl maleate; diallylphthalate; triallyl cyanurate; allyl methacrylate; ethylene glycoldimethylacrylate; pentaerythritol triacrylate; pentaerythritoltetraacrylate; ethyl acetoacetoxylmethylacrylate; diacetone acrylamide;allyl acrylamide; or mixtures thereof.
 18. The vinyl acetate-ethylenecopolymer-based emulsion according to claim 11, wherein thecopolymer-based emulsion has a solid content of about 40 to 70% byweight based on the total weight of the emulsion.
 19. A process forpreparing the vinyl acetate-ethylene copolymer-based emulsion accordingto claim 11, said process comprises emulsion polymerizing a monomericcomposition comprising: (1) about 65-95 pphm of a moiety derived fromvinyl acetate; (2) about 5-35 pphm of a moiety derived from ethylene;and (3) about 0-10 pphm of a moiety derived from other comonomers orfunctional monomers, in the presence of about 1-5 pphm of a surfactantand about 0-10 pphm of a polymeric protective colloid asemulsifier/protective colloid.
 20. The process according to claim 19,wherein the emulsion polymerization is carried out in the presence of aredox initiator.
 21. The process according to claim 20, wherein theinitiator is selected from ammonium persulfate, sodium persulfate,hydrogen peroxide, tert-butyl peroxide, sodium formaldehyde-sulfoxylate,disodium 2-hydroxyl-2-sulfinatoacetate, ascorbic acid, erythorbic acid,alkali metal salts of ascorbic acid, alkali metal salts of erythorbicacid, sodium bisulfite, sodium sulfite, sodium metabisulfite, sodiumthiosulfate, or mixtures thereof.
 22. A low odor paper coatingcomposition comprising the vinyl acetate-ethylene copolymer-basedemulsion according to claim
 11. 23. (canceled)